With the two-test series a week away, New Zealand will try to save face at Westpac Stadium in the fifth one-day international after Australia cruised to a six-wicket victory in Auckland on Thursday night to clinch the series 3-1.
A lack of ruthlessness with the bat was the biggest concern from games three and four, particularly at Eden Park when New Zealand was in command at 120 for one in the 20th over, and Brendon McCullum in full flight, before being dismissed for 238 off 44.1 overs.
Greatbatch insisted it was not all doom and gloom and wanted to ensure his batsmen did not completely go into their shells.
"We are playing against the best side in the world who've won three World Cups. We need to be realistic as well. We had a real chance to go 2-0 up [in game two in Auckland] and we didn't take it. We can look at what we've done well and not so well and try to make amends tomorrow," he said.
"We're trying to get these guys to play as fearlessly as they can against the best in the world which is not always easy. You've got to encourage them to play their best game and there's going to be some mistakes along the way. We have to attack the opposition but there's got to be some smarts there too."
Greatbatch, whose side is ranked fourth in the world in one-day cricket, said the difference between the sides was Australia's ability to seize momentum in a 10-over period.
A classic example of that was when New Zealand lost five for 34 in 66 balls on Thursday, including Ross Taylor, McCullum, Scott Styris and captain Daniel Vettori.
For once, Mitchell Johnson was not the chief tormentor and James Hopes and spinner Nathan Hauritz did the damage.
"Hopefully, you've seen the fight in players across the board. Our batting hasn't been consistent enough, It needs to be more ruthless and guys need to finish the job.
"The individual needs to take personal responsibility to be better. Whoever it is if he's on 50 he needs to score 100, if he's the fifth bowler he needs to concede 40 instead of 60."
Defending a rain-reduced 200 off 34 overs, Shane Bond and Daniel Vettori applied the pressure but Daryl Tuffey - who was unlucky not to remove Ricky Ponting lbw for 19 - Tim Southee and James Franklin were expensive.
Greatbatch said spinner Nathan McCullum was likely to come in for his first match of the one-day series, possibly at the expense of a struggling Franklin, who was shifted down to No 8 in the order on Thursday.
Axed batsmen Peter Ingram and Neil Broom returned to Plunket Shield cricket yesterday, so debutant Shanan Stewart will get another chance after he faced just nine deliveries before lofting a catch off Hauritz.
Greatbatch said the test series was an exciting prospect despite his side being "huge underdogs", and today was a chance to show it would not roll over.
He tried to temper expectations which had skyrocketed after the Napier win and the near miss in Auckland - "a game we should have won".
"Our side is not world class, We're ranked fourth in the world and we're playing No 1. If we can get a game off them tomorrow that's three out of seven [including drawn two-match twenty/20 series], which isn't good enough but it's going towards competing against the world No 1 consistently."
Australia signalled paceman Clint McKay and replacement batsman George Bailey would get a run, and Ryan Harris (toe) might earn a rest.
• NEW ZEALAND v AUSTRALIA
Wellington, today 2pm
New Zealand (from): Daniel Vettori (captain), Brendon McCullum, Martin Guptill, Ross Taylor, Shanan Stewart, Scott Styris, Gareth Hopkins, James Franklin, Nathan McCullum, Daryl Tuffey, Shane Bond, Tim Southee, Michael Mason.
Australia (from): Ricky Ponting (captain), Shane Watson, Brad Haddin, Michael Hussey, Cameron White, Adam Voges, George Bailey, James Hopes, Mitchell Johnson, Nathan Hauritz, Clint McKay, Doug Bollinger, Ryan Harris.
Umpires: Asad Rauf (Pakistan), Gary Baxter (New Zealand).
TAB odds: Aust $1.33, NZ $3.10.
